Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/17/21

Area Forecast Discussion
National Weather Service La Crosse WI
1000 PM CST Tue Feb 16 2021 .SHORT TERM...(This evening through Wednesday) Issued at 222 PM CST Tue Feb 16 2021 We`ll start this discussion off with some good news, as early afternoon ASOS/AWOS observations showed temperatures above zero across the entire forecast area, with some spots even getting into the teens! Now the bad news is that we`ll be getting well below zero again tonight and some spots could west of the Mississippi River could get close to wind chills of -20. That said, not thinking we`ll need an advisory as those wind chills look like they`ll be pretty spotty with temperatures staying up a bit with as winds become southerly and clouds move in. Attention then turns to light snow chances Wednesday as southerly flow ushers in moisture and some weak isentropic lift spreads in by the afternoon. Latest short term guidance has trended toward favoring light snow development across south-central and southeastern Minnesota into north-central Wisconsin. In addition, some precip could extend northward from a slightly stronger system well to the south and possibly clip parts of northeast Iowa and far southwest Wisconsin. Overall, the forcing looks weak and given the light southerly flow, moisture return ahead of the forcing will be lacking quite a bit. As such, many model soundings show that it`ll be a struggle for enough saturation through the column for precip, at least for any extended period of time. Still think at least some light accumulations will be possible for much of the area, especially given a deep, surface-based DGZ leading to high snow ratios. If forcing or moisture trend upward, could be a sneaky 1+" for someone, but as it stands, thinking 3/4 of an inch will be toward the high end of amounts, but still enough that there could be a few slick spots. .LONG TERM...(Wednesday night through Tuesday) Issued at 222 PM CST Tue Feb 16 2021 Light snowfall overnight Wednesday will end Tuesday morning from west to east as the short wave exits the region. Some flurries may persist into Thursday morning as another weak shortwave swings through the area while some relatively decent saturation remains in the area. Otherwise, dry weather is expected to persist into the weekend. Temperatures begin their slow recovery to near seasonable normals throughout the week as an upper-level trough progresses eastward through the central plains and upper midwest of the US. Afternoon high temperatures will be in the teens to low 20s to the end of the week. Flow aloft becomes more northwesterly as an upper-level ridge builds in from the west. As this subtle ridge moves eastward through the area over the weekend, 850 mb temperatures increase to near -5C by Sunday with surface temperatures then increasing into the upper 20s to low 30s Sunday afternoon. This warming trend is anticipated to continue into early next week with ABOVE freezing temperatures becoming more likely on Monday and Tuesday afternoons. Another round for precipitation enters the forecast on Sunday. However, it is still too early to determine exact details, so have decided to stick with the blended model guidance bringing in some low chances. This system will be closely monitored as there is a potential for areas to receive accumulating snow. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1000 PM CST Tue Feb 16 2021 Cigs: weak upper level shortwave will bringing increasing clouds overnight, with lowering as Tue wears on. The GFS continues to favor MVFR cigs for KRST while the NAM and to some extent the RAP does not. Not finding much in satellite/sfc obs to trend the forecast toward one solution or the other. Will stick with previous forecasts and bring MVFR into KRST and hold KLSE VFR. Anticipate refinements and details become more clear. WX/vsby: weak shortwave and weak thermodynamics, but with cold air in place, the forcing could/will be enough to squeeze out light snow/flurries. Not expecting IFR vsbys, but some dip into MVFR seems possible/likely. Any accumulation should hold to just a few tenths. Lesser threat at KLSE. Winds: staying light through the period, but turning more south/southeast. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...CA LONG TERM...Peters AVIATION...Rieck
Area Forecast Discussion
National Weather Service Dodge City KS
510 PM CST Tue Feb 16 2021 ...Updated Aviation Discussion... .SHORT TERM...(This evening through Wednesday) Issued at 341 PM CST Tue Feb 16 2021 The arctic airmass was slowly but surely starting to modify -- emphasis on slowly. Here at DDC, we reached +10F early in the afternoon before stabilizing. We got perhaps a couple of degrees warmer than forecast, despite the cloud cover and flurries, most likely due to some mechanical mixing from stronger south winds today, allowing for mixing of some slightly warmer air just off the surface. All in all, the forecast update is for tonight through tomorrow night is not all that different. Tonight`s snow event will remain just south of southwest Kansas across Oklahoma, and we have even pulled back some on the Barber County snowfall forecast -- to around one-half inch (and that would mainly be along the Oklahoma border). As far as wind chills go, we expect as temperatures fall back down toward 0F tonight, wind chills will fall back down to -15 to -18F or so with continued south wind 7 to 10 mph. A Wind Chill Advisory will remain in effect (except for the far southwest counties) until mid to late morning Wednesday. Today will mark the 9th straight day with temperature below 20F officially at Dodge City. This ties for 2nd place for longest run of days below this temperature. That 2nd place was the great arctic outbreak of 1899, so this is indeed quite the accomplishment in terms of duration for such an arctic outbreak considering the period of record for Dodge City goes back to 1875. Number 1 on that list is the cold wave of late February/early March of 1960 at 11 straight days. There is a very reasonable possibility we may push this streak to 10 days tomorrow. The airmass will continue to modify tomorrow, but will it modify by 10 degrees over today`s high? That will be the main question. Dodge City will likely start right around 0F early in the morning, and while there will likely be breaks in the clouds in the afternoon, the wind will be very light if not calm much of the afternoon. This will limit mixing and prevent a rapid temperature rise. In fact, the latest HRRR model runs now keep afternoon temperatures solidly in the mid teens across southwest Kansas, including Dodge City, during the time of typical diurnal max of late afternoon. .LONG TERM...(Wednesday night through Tuesday) Issued at 341 PM CST Tue Feb 16 2021 As mentioned in previous Long Term discussions, a much-welcomed rebound to temperature normalcy is forecast. The transition days will be Thursday and Friday, but even Thursday may be tough to break mid 20s across much of the area. Friday, the airmass modification will continue and much of the snow melt will really commence across western Kansas. Insolation will go largely into snow melt, so it will be difficult, even on Friday, to exceed the mid 30s, but it will certainly feel so much better than the 10F we are seeing this afternoon. Another fast-moving, low-amplitude shortwave trough will move out of the West and across the Rockies over the weekend, but this system will be moving too quickly to tap into any moisture for precipitation across southwestern Kansas. We will probably see a pause in the continued warm-up late in the weekend with slight cold air advection in the wake of this trough, but the airmass will be modified substantially by downslope trajectories from Wyoming higher terrain. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 502 PM CST Tue Feb 16 2021 BUFR soundings continue to indicate a layer of moisture in the 1000 to 5000ft AGL level overnight and early Wednesday across southwest Kansas. Models however differ on where the low ceilings will be located in this moist layer. Based on the latest trends of the short term models it appears that ceilings will begin in the 1000 to 2000ft AGL level tonight and then begin to improve after 12z Wednesday into the 2000 to 3000ft AGL level. After 18z there may even be a few breaks of sun as ceilings increase to greater than 3000ft AGL. Southeast winds at around 10 knots early tonight will become light and variable early Wednesday morning. && .PRELIMINARY POINT TEMPS/POPS... DDC -1 17 3 27 / 10 0 0 0 GCK -2 18 3 25 / 0 0 0 0 EHA 2 21 8 28 / 0 0 0 0 LBL -3 17 2 26 / 10 0 0 0 HYS -1 19 3 27 / 0 0 0 0 P28 4 17 5 26 / 40 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... Wind Chill Advisory until 10 AM CST /9 AM MST/ Wednesday for KSZ030-031-043>046-061>066-075>081-086>090. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...Burgert
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
659 PM CST Tue Feb 16 2021 .UPDATE... Overall, forecast is in good shape at the present time. Made some minor adjustments to the grids, the main being to add a mention of snow possibly mixing in across our extreme northern CWA with the onset of the precipitation. HRRR model soundings look favorable for this before the warm nose strengthens by midnight. && .PREV DISCUSSION... /ISSUED 523 PM CST Tue Feb 16 2021/ AVIATION... VFR conditions prevail, but MVFR then IFR conditions are expected overnight as moisture increases across the area. As the moisture increases, areas of freezing rain will be expected across the northern areas with AUS the most impacted. Will prevail freezing rain and sleet there as some sleet will also be possible. For SAT will tempo the mention of freezing rain as probabilities are less to the south. Precipitation should move east of the terminals by 12z with LIFR conditions possibly persisting through the morning and into the afternoon hours tomorrow. PREV DISCUSSION... /ISSUED 339 PM CST Tue Feb 16 2021/ .DANGEROUS WINTER WEATHER CONDITIONS TO CONTINUE THROUGH THURSDAY... Key Messages: * Another round of mainly freezing rain and sleet will returns to South Central Texas tonight with a second round of Wintry Mix expected tomorrow night into Thursday. Additional ice accumulations will combine with existing ice on the ground to make outdoor travel dangerous through Thursday. If you must travel, keep an extra flashlight, food, blankets, and water in your vehicle in case of an emergency. * Rotating power outages expected to continue. * Check frequently on those without heat and water. Protect plants and pipes. Provide warm shelter for pets. SHORT TERM (Today through Wednesday)... While we had another day of sunshine for most of the morning temperatures have remained below freezing across South Central Texas. Low 20s to a few `lucky` areas seeing lower 30s are where temperatures are this afternoon. As of now cloud cover has begun to spread into South Central Texas from the south and from the northwest. While some western areas may see the sun again tomorrow, areas along the I-35 corridor will be entering another cloudy and wintry weather pattern. Synoptically the CONUS is experiencing a large scale trough with embedded shortwaves. One of those shortwaves will move across north Texas overnight tonight into tomorrow. At the same time a surface low pressure system will form across the middle Texas Coast. It is these two features that will provide the lift needed for the next round of wintry precipitation on the way tonight. Model soundings support mainly a freezing rain pattern for tonight as overnight lows again drop into the 20s area wide due to cold air advection at the surface. In the mid-levels areas of warm air advection will work to produce a slight warm nose. This could lead to some sleet mixing in across parts of the Hill Country, Austin Metro and parts of Williamson and Lee Counties. This will end up being a bit of a saving grace across these areas in terms of overall ice accumulations. In general across theses areas as much as a tenth (0.10) of an inch of new ice accumulation is possible. A few areas may see as much as a quarter (0.25) inch of new ice, especially across parts of Williamson and Lee Counties, but again, if more sleet is able to mix in these overall accumulations will be lower. Further south along the I-35 corridor towards the San Antonio, along the Coastal Plains and west across the Edwards Plateau as much as 0.05 inches of new ice are possible. In terms of timing the two areas of precipitation should begin to form late this evening into the overnight hours: one across the Hill Country with the shortwave, and the other across the southern Edwards Plateau and Coastal Plains with the Coastal Low. Precipitation should fill in and become widespread across all of South Central Texas by midnight. While no one should be out on the roads or really considering travel at this point, precipitation does generally come to an end after sunrise tomorrow, with lingering mix of rain and freezing rain east of Interstate 35 through the late morning to the noon hour. Tomorrow afternoon looks dry across the area with some sunshine returning across the Rio Grande and Edwards Plateau. Afternoon highs should range from the low 30s across northern areas to the upper 40s and 50s in area that see sunshine. This should at least start to help melt the snow and ice across some areas. Takes Deep Breath, looks for the light at the end of the tunnel, one more event to go! The base of the trough will finally move across Texas Wednesday night into Thursday morning. Models are still iffy with this event, having pushed it back more into the day on Thursday which will be discussed below. Of the two events (tonight vs. tomorrow night) this is certainly the lower confidence of the two, but it has started to become a clearer picture today. Rain mixed with freezing rain should begin during the evening and early overnight hours Wednesday across the Rio Grande Plains and then spread eastward through the night, changing to a wintry mix of freezing rain, sleet, and snow after midnight. Accumulations with this activity are expected to generally be light, but certainly won`t help the ongoing situation with snow (from Sunday night) and ice (from tonight) on the ground. Based on the uncertainty with the second system we have elected to make no changes at this time to our Winter Weather Hazards. A Winter Storm Warning is in effect for most of the area due to the threat of ice accumulations with tonights system. With lower impacts along the Rio Grande for tonights event have continued the Winter Weather Advisory in those areas. Future shifts will need to look at the second event and determine if an upgrade to Winter Storm Warning is needed, or if the Winter Weather Advisory will suffice. LONG TERM (Wednesday Night through Monday)... Wintry precipitation chances hold over into the day on Thursday as the base of an upper level trough advances across the region with a tailing cold front. The latest thinking is for the greatest concentration of wintry precip will occur to the west of I-35 across the Rio Grande Plains and Southern Edwards Plateau. For further east, couldn`t rule out a slight chance for wintry mix. Considerable uncertainty remains regarding this expected final round of wintry precip as the latest model guidance vary on the amount of QPF that develops with the associated lift from this system. The thermodynamic analysis show that the temperatures will be more marginal at the surface while colder air moves in aloft with the base of the trough, helping to erode the pre-existing warm nose. A wintry mix prevails into the morning on Thursday but may transition to nearly all snow later during the day with the last of the precipitation before the conditions dry out with the base of the trough moving eastward. Snowfall accumulations will continue to be refined regarding this system but areas mainly to the west across the Southern Edwards Plateau into the Rio Grande Plains are expected to see around an inch of accumulation while areas further east see little to no accumulation. Temperatures have been lowered slightly with areas seeing highs in the low to mid 30s to the north and east while locations further west and south may get into the low 40s during Thursday afternoon. With skies clearing into Thursday night, do expect another very cold night with temperatures in the teens to lower 20s when waking up Friday morning. Upper level pattern transitions to a more zonal flow from Friday into the weekend with a warming trend back towards climatological average by Sunday as surface winds finally become southerly as we go through the weekend. Plenty of sun will be expected early in the weekend before becoming more cloudy into Sunday. A shortwave trough passing across the central Plains on Sunday into early Monday sends a cold front across South-Central Texas sometime Sunday afternoon into Sunday night. This frontal passage looks to stay generally dry but a stray light shower cannot be completely ruled out. Drier and slightly cooler air does push in behind the front into Sunday night and early Monday morning. Monday then warms up during the day as solar radiation takes over under mostly sunny skies. Temperatures continue to warm into Tuesday and midweek with zonal flow aloft and the return of a southerly surface flow. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 20 35 25 35 19 / 80 20 20 20 0 Austin Bergstrom Intl Airport 19 35 24 35 18 / 80 20 20 20 0 New Braunfels Muni Airport 23 39 28 38 20 / 60 20 30 20 0 Burnet Muni Airport 19 34 22 34 18 / 80 10 20 20 0 Del Rio Intl Airport 26 54 31 41 23 / 20 - 50 40 0 Georgetown Muni Airport 17 34 23 34 16 / 90 20 20 20 0 Hondo Muni Airport 22 48 27 39 19 / 30 - 40 30 0 San Marcos Muni Airport 19 37 24 36 18 / 70 20 30 20 0 La Grange - Fayette Regional 25 36 28 36 20 / 80 50 20 10 0 San Antonio Intl Airport 23 43 28 38 21 / 40 10 30 20 0 Stinson Muni Airport 24 44 28 39 20 / 40 10 30 20 0 && .EWX WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 6 AM CST Thursday for Atascosa-Bandera- Bastrop-Bexar-Blanco-Burnet-Caldwell-Comal-De Witt-Edwards-Fayette- Gillespie-Gonzales-Guadalupe-Hays-Karnes-Kendall-Kerr-Lavaca-Lee- Llano-Medina-Real-Travis-Williamson-Wilson. Winter Weather Advisory until 6 AM CST Thursday for Dimmit-Frio- Kinney-Maverick-Uvalde-Val Verde-Zavala. && $$ Short-Term/Aviation...Hampshire Long-Term...17
Area Forecast Discussion...Updated
National Weather Service Peachtree City GA
945 PM EST Tue Feb 16 2021 .Update... Have adjusted min temperatures down a couple of degrees based on trends. Otherwise no changes. 41 .Previous... .SHORT TERM /Tonight through Wednesday Night/... Arctic airmass has finally surged into the CWA this morning before stalling, bringing with it some light snow showers and even a dusting of snow in some locations scattered about the state where a brief heavier snow shower was able to form. Cloud cover that remained in place across the NWern 3/4ths of the CWA has finally begun to dissipate in spots allowing the sun to peak through in some locations. Temperatures this afternoon will warm only a little in some locations as a result before dipping a little bit lower tonight. Aloft, deep 500 mb trough is still in place to the west, so we remain under a SW flow regime. Another shortwave will move across the deep south around that trough tonight into Wednesday and interact with the stalled frontal boundary across the southeast, generating another surface low that will bring rain and the potential for some wintry weather to our CWA. Forecast on Wednesday night is simply put, complex, so please give your local friendly meteorologist a break if you can. Surface low will send moisture surging back northward on Wednesday into Wednesday night with a warm front setting up somewhere in central Georgia. To the north of this front, isentropic lift will allow for moderate rainfall to overspread the region, bringing the potential for some isolated flooding/flash flooding risks, especially where heavier pockets of rain do form. Some thunder could be possible with this as well as there is some elevated instability present north of the front, though not much. To the south, thunder will certainly be possible as a little more instability is noted, though better chances for severe weather appear to be on Thursday after sunrise, and will be covered by the long term discussion below. The complicating factor to this forecast will be a bit of a wedge that will be in place across the northern portion of the forecast area. While not a traditional wedge as we think of it with forcing from the NE CONUS, this appears to be more remnants of the very cold air across the area being trapped up against the mountains given the very southern location of the sfc low. With cold air in place, some locations in the NE mountains and in NW GA look to hover at or just below freezing for a few hours while precipitation overspreads the area. Given very prominent warm nose at 850 mb reaching 2+ C per HRRR and other soundings, the likely precipitation type would be either sleet or freezing rain depending on the depth of the cold air entrenched below. Leaning towards a more freezing rain solution with what most model sounding profiles look like in the low levels, and have introduced that in this package with ice accumulations of a few hundreds of an inch in parts of NE and NW GA. At the moment, not expecting much in the way of impacts from this, given it will be 1) short duration (only a few hours overnight), 2) light accumulations, 3) marginal temperatures which would likely only allow for glazing of more elevated surfaces, and 4) would quickly melt as the sun rises and additional rain moves into the area. Lusk && .LONG TERM /Thursday through Tuesday/... Active weather will be the story across north and central Georgia on Thursday as an upper-level trough traverses Texas and the Deep South, while moisture continues to overspread the CWA. A surface low is progged to develop over the northern Gulf of Mexico and track northeastward from southeast Alabama into central Georgia through the day. As such, the threat for strong to severe storms on Thursday is maximized over central Georgia, where moisture return along a northward-advancing warm front overlaps with deep- layer shear and favorable upper-level and lower-level jet dynamics. As it stands now, SPC has a Slight Risk on Thursday for the portion of the CWA just south of Columbus and Macon, and west of Vidalia. However, lower-end instability could prove to be a limiting factor for storm strength and/or coverage. In addition to the storm threat, PWATs are progged to reach 1.5" to 1.75" across much of central Georgia on Thursday (for reference, the daily max PWAT for February 18th per FFC sounding climatology is 1.34"). Storm total QPF for this system is 1.5" to 2.0" area-wide with isolated totals up to 2.5". Will need to monitor for potential hydrology issues, especially across the southeastern portion of the CWA where some rivers, creeks, and streams are swollen from recent rains. As the last of the rain pushes through the eastern CWA early on Friday morning, cold air will push into north Georgia and meet up with lingering moisture. A rain/snow mix will be possible across portions of north Georgia between 04z and 12z Friday, though impacts appear to be minimal at this time with any accumulations just a tenth of an inch at most. Much of Friday, Saturday, and Sunday will bring quiet weather as surface high pressure spreads across the Southeast beneath upper- level ridging. The next system to bring precipitation will arrive on Monday morning. There is much uncertainty this far out, but it appears that a wintry mix could be possible across the higher terrain of northeast Georgia in the morning. Elsewhere, liquid precipitation is expected. Martin && AVIATION... 00Z Update... VFR through the period...until the last few hours when ceilings lower to MVFR around 05z Thursday. Northwest winds less than 8 kts overnight will shift to the east around 12z with winds in the 10 to 12 kt range. //ATL Confidence...00Z Update... High on all elements. 41 && .PRELIMINARY POINT TEMPS/POPS... Athens 27 50 38 48 / 0 20 100 100 Atlanta 26 49 40 51 / 0 30 100 90 Blairsville 21 45 34 46 / 0 20 100 90 Cartersville 22 49 37 50 / 0 30 100 90 Columbus 28 53 45 63 / 0 30 90 90 Gainesville 27 47 36 47 / 0 20 100 100 Macon 27 54 44 63 / 0 20 80 90 Rome 22 50 37 50 / 0 30 100 90 Peachtree City 25 51 40 54 / 0 30 90 90 Vidalia 32 54 48 72 / 0 20 60 80 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...41 LONG TERM....Martin AVIATION...41
Area Forecast Discussion
National Weather Service Fort Worth TX
648 PM CST Tue Feb 16 2021 ...New Short Term, Aviation... .SHORT TERM... /NEW/ /Tonight through Wednesday Night/ Another wintry event is unfolding across the Southern Plains this evening as snow has spread back into North Texas, mainly north of I-20. A strong upper trough is spreading into West Texas at this hour and will continue to deepen overnight thanks to upstream ridge amplification off the West Coast. Strong synoptic scale forcing for ascent will overspread the region through tonight, but the more impressive forcing will come in the form of 925-700 mb warm advection. It`s rather unusual for us to see snow with southerly flow below 700 mb as this almost always results in a strong warm nose and freezing rain events. However, given that this layer is quite cold from our arctic airmass, it`ll likely remain below freezing through the event. RAP forecasts of 925-850 mb warm advection peak tonight from midnight to 4 am with rates of 25-35 C/12hr which are pretty incredible rates of warming, yet the same guidance keeps the thermal profile near or just a touch above freezing across the Metroplex. This should result in mostly snow for the Metroplex and areas to the north. Areas to the south will likely see sufficient warming for areas of sleet and some freezing rain to occur. The freezing rain is most likely for areas south of a Lampasas to Hillsboro to Canton line where additional ice accumulation could approach 1/4 inch. We`ll continue to monitor this warm advection through the evening though as additional warming could result in more significant icing across our southeast counties. Total snow accumulations should range from 2 to 5 inches from the Metroplex northeast...although there could be some isolated pockets of 6+" near the Red River through Wednesday morning. Snow amounts will taper off to generally around an inch or less south of the Metroplex. All of this activity will move off to the east early Wednesday morning, however the main trough axis will slowly spread through the Southern Plains and additional light snow will be possible through the day mainly along and north of I-20. Little additional accumulation is expected during this time. It`ll continue to be cold tonight, although not nearly as cold as last night, with temperatures in the mid teens areawide. Lingering cloud cover will hold highs in the mid/upper 20s on Wednesday. Dunn && .LONG TERM... /Issued 252 PM CST Tue Feb 16 2021/ /Saturday onward/ After a really rough stretch of winter weather (to put it mildly), things are looking a lot better through the weekend and especially into next week. Temperatures should rise above freezing by around noon on Saturday. After that, we should stay mostly above freezing through at least the middle of next week as upper-level ridging builds across the region. The weather looks mainly dry as well. The one small exception will be on Sunday. On Sunday, a weak upper-level shortwave trough will move through the Southern Plains, driving a weak cold front through at the surface. This may spark a few rain showers in our eastern counties where moisture is the most abundant, but we are not anticipating any frozen precipitation or severe weather. Just some light rain, if that. This weak cold front may also knock a few spots just below freezing on Sunday night, with a light freeze forecast for areas north and west of the Dallas/Fort Worth Metropolitan Area. Heading into next week, the upper-level ridge will build over us, bringing temperatures into the 60s for the early part of the week, with overnight lows remaining above freezing. These warmer temperatures along with abundant sunshine should allow for snow and ice to melt quickly. Stay tough, Texas. Things are looking much better by early next week. Godwin && .AVIATION... /NEW/ /00Z TAFs/ VFR prevails throughout the D10 airspace this evening although conditions will quickly deteriorate as it is snowing above us at this time. Some dry air aloft will quickly saturate and allow snow to make it to the ground over the next 1-2 hours. Further snow development is expected later tonight with IFR expected around midnight. We`ll have a TEMPO for 1/2SM SN at DFW/AFW from 6-9Z based on their proximity to the heavier snow bands which should lie between the Metroplex and the Red River. Otherwise, we`ll continue to monitor the other sites for further reductions in visibilities overnight. The main snow should taper off by early Wednesday morning, but additional light snow may persist into midday. IFR cigs should prevail most of the day before seeing some improvement after Sunset Wednesday. At Waco, some snow will be possible, but warmer conditions aloft should result in some sleet and freezing rain during the overnight hours. FZRA should prevail by 8Z and will continue into early Wednesday morning. IFR will prevail after the precipitation ends. Dunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 17 27 18 29 13 / 100 60 5 5 0 Waco 18 29 21 31 14 / 100 20 10 10 0 Paris 16 26 18 30 10 / 100 100 10 10 0 Denton 15 26 16 30 9 / 100 60 0 5 0 McKinney 16 26 18 30 10 / 100 70 5 5 0 Dallas 19 27 21 32 15 / 100 50 5 5 0 Terrell 17 27 19 30 12 / 100 80 5 10 0 Corsicana 20 28 22 31 16 / 100 70 10 10 0 Temple 16 31 21 32 14 / 100 20 20 20 0 Mineral Wells 16 26 16 29 11 / 60 20 5 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 6 AM CST Thursday for TXZ091>095- 100>107-115>123-129>135-141>148-156>162-174-175. && $$
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
1004 PM CST Tue Feb 16 2021 .UPDATE... 955 PM CST Tweaks to the forecast have been continuing to maintain higher lake effect snow chances into Porter County, IN through early overnight, as well as extending clouds over some parts of northeast Illinois longer and bumping up forecast lows there. While lake effect snow (for this event) is nearing the end, it has for most of the evening had a concentrated area of moderate snow showers into Porter County. This has been well established on low- level convergence and a presumed meso-low over the southern part of the lake per analyzed wind streamlines on high-res guidance. As has been the case, the lake effect parameters are not through the roof (for instance equilibrium levels of only 6,000 ft), but because of the very cold low-levels, the dendritic growth zone is overlapped by the steep lapse rates and cloud depths. We suspect some parts of Porter County have received around to a little over 2 inches this evening based on radar and webcam imagery, and could finish with some nighttime totals of 3-4 in isolated spots of northern Porter. Even if that were to happen, feel the nature of this after the prolonged event is best handled with G-NOWs, a Special Weather Statement, and other messaging. Elsewhere, clouds from the lake effect fetch have meandered across the south Chicago metro. Think these will stay due to diminishing 850-925 mb flow yet an inversion still in place above that (as seen on 0230Z aircraft sounding data into MDW). The RAP seems to be initializing this well and this solution keeps these clouds in this area for several more hours before then moving them north as the cloud-bearing blow becomes southerly. Clouds are having a large influence on temperatures, not surprisingly with a 1025 mb high moving overhead and fresh snow cover. Those areas that are clear or can clear for several hours will be subzero, and already have some of those readings including -6 in Rochelle. Patchy shallow fog is certainly possible in parts of north central ILlinois and in the far southern forecast area, though confidence on that is low. Do not see that being a huge deal if it develops, but isolated pockets of dense at just a few feet off the ground is possible. MTF && .SHORT TERM... 229 PM CST Through Wednesday... The lake effect machine continues this afternoon, but the better convergence signal has shifted out over the lake and into northwest Indiana. There is still a loosely organized band with occasional 25 dBz echoes, but the band is also fairly coherent across much of the entire length of the lake. Therefore, these have infrequently reduced visibility in LaPorte county to 1/2SM. Forecast convergence/low level omega does show an uptick into Porter county through about mid evening or so, and thus we are not fully in the clear yet where some impactful lake effect snow may occur, so use caution if traveling near the lake in northwest Indiana through the evening. For the rest of the area, expect cloud cover to slowly erode (where it currently is now) through the evening as high pressure across the plains/upper Midwest scoots on in. Light winds could lead to some fog across north central IL and there is some guidance suggesting this, but this is of low confidence and will need the evening shift to take a bit closer look at this. With the light winds and fresh snowpack, it will be a cold night with subzero temperatures. Some of the colder guidance pushes -10 across our colder outlying areas of north central IL. The snow train continues later Wednesday, though maybe this part of the ride will be a little less bumpy. Our next disturbance is back across the Texas panhandle. This will spread toward the region later Wednesday. This system track will place us on the less favorable side of the upper jet, though a modest uptick in isentropic ascent south of Chicago will lead to a generally lighter snow shield during the afternoon. More limited ascent and drier air near Chicago suggests the more widespread, though still lighter precipitation may occur later Wednesday night into Thursday as some interaction with a northern stream trough aids in better forcing for snow. KMD && .LONG TERM... 300 PM CST Wednesday night through Tuesday... As we head into the extended period the high amplitude trough across the central CONUS will gradually begin to lift to the northeast late in the week with a quick moving trough following up behind for the weekend with a warming trend possible early next week. Although not as impactful as the previous 48 hours, light snow remains in the forecast Wednesday evening into Thursday as a weaker disturbance moves through the trough the area. There remains considerable variability in the model guidance, similar to how the past several low QPF snow events we dealt with the past few weeks were often underdone. Because of this, felt confident enough to maintain at least "chance" PoPs Wednesday evening into the overnight hours with a follow up southern-stream wave moving through. Some lake effect precip may still linger into Thursday although some of the guidance has backed off on the more bullish lake effect bands. Heading into Friday, surface high pressure will set up shop over the area which should help clear skies out a bit. This combined with lighter winds and the deep snow pack will allow temperatures to drop back into the negatives late Friday night into Saturday morning. Although not as cold as last weekend, wind chill values in the -5 to -15 range will be possible. As the upper trough begins to lift east northeast the surface high shifts into the eastern CONUS which will bring a return of southerly flow to the area late Saturday into Sunday beginning a potential warming trend into early next week. A more potent wave moves through on Sunday with a surface low developing on the left exit region of a strong upper jet. Model guidance remains somewhat varied on the precip type for this event. However, with such a deep snow pack still in place, suspect that the GFS guidance is still too warm and prefer the ECMWF solution favoring mainly a snow event for our area. For now keep the rain/snow mix line mainly along and south of the Kankakee River valley. Petr && .AVIATION... For the 00Z TAFs... 533 PM...Forecast concerns include... Chance for light snow Wednesday afternoon into Wednesday evening. Chance for light fog early Wednesday morning. Lake effect snow showers continue into northwest IN, mainly east of gyy though there have been a few flurries here at lot late this afternoon along with some virga and carried flurries at gyy for a few hours this evening. Otherwise, dry weather is expected until Wednesday afternoon when there will be another chance for light snow across the entire area. There remains some uncertainty with this system as it will likely be weakening as it lifts across the area. There are also some timing differences and opted to carry tempo mention centered around 00z but some prevailing light snow mention may be needed as trends emerge. If light snow develops...vis in the 2sm range can be expected along with mvfr cigs. High pressure will move across the area with light westerly winds likely becoming light and variable or calm tonight. Winds will turn southerly Wednesday morning and southeasterly by afternoon. The light winds and clearing skies may lead to some light/shallow fog developing away from the Chicago metro area. Confidence if very low and did not include any fog mention but its possible for some fog to develop by morning, especially in the usual/rural locations. A bkn/ovc 4-5kft deck over the Chicago area is expected to slowly shift southeast and dissipate this evening into the overnight hours but low confidence for timing. A mid deck will spread across the area Wednesday ahead of a lower, 3-4kft, vfr deck in the afternoon. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Miami FL
903 PM EST Tue Feb 16 2021 .UPDATE/MESOSCALE DISCUSSON... The cold front that gradually moved across South Florida during the day today has stalled across the nearshore Atlantic waters off South Florida -- evident via northerly surface winds across the east coast metros and a stalling band of pre-frontal convection over the Atlantic waters. As the primary mid-level shortwave trough ejects offshore the New England states, there may be a tendency for rich moisture (PWs near 2 inches) to lift back northward across the eastern portions of South Florida along the stalled boundary overnight. While large-scale forcing for ascent will be minimal, northward positive theta-e advection and potentially coastal/frictional convergence could allow for mesoscale ascent and re-development of coastal convection during the overnight hours. In addition, latest RAP analysis suggests that a mesoscale low may be developing offshore Palm Beach County which could further aid in northward moisture transport and associated continued instability. Generally west-southwesterly steering currents aloft could potentially aid in convective training and backbuilding along the immediate east coast metros during the overnight hours, which would raise increasing flooding concerns owing to todays heavy rainfall and high tide around midnight. The overnight flooding risk remains conditional upon convective residence time along the east coast metros. The 00Z MFL RAOB shows a favorable environment for heavy rainfall with a deep warm cloud depth, PW of 1.82 inches, and weak mid- level lapse rates. In addition, marginal deep-layer shear around 20 to 25 knots could aid in brief updraft organization and localized heavy rainfall. The areas that got hit hardest with heavy rainfall today are portions of the coastal/metro Miami area and portions of metro Broward County. The WPC continues to maintain a marginal risk of excessive rainfall/flash flooding for the east coast metros overnight. Please keep up with the latest from NWS Miami and the WPC. && .PREV DISCUSSION... (Issued 719 PM EST Tue Feb 16 2021) AVIATION(00Z TAFS)... Brief periods of IFR are still possible over the Atlantic terminals through around 05Z as a front is stalling around South Florida. Main impacts will be low cigs, possibly in the bkn004-005 range with isolated heavy rain. Otherwise, VFR is expected through 15Z, then periods of MVFR cigs/vis may again develop Wednesday afternoon. Winds should remain light and variable through 15Z. PREV DISCUSSION... (Issued 239 PM EST Tue Feb 16 2021) DISCUSSION... Short Term (Tonight through Wednesday): A cold front will continue to move eastward generally through the region this afternoon and evening. The problem is where exactly does this front stall? Over the Gulf Stream would be enough to transition winds to an offshore flow and reducing rain chances. However, a stall right over the Atlantic metro could be bad news. A stall over the metro would mean not only continued rain and storm chances, but perhaps some flooding potential as well. In fact, PWATS from this morning`s sounding are right around 1.8" or so...which to put that into perspective is roughly within the 99 percentile for this time of year. With the boundary over and a unidirectional wind profile, hydro concerns may arise, despite antecedent conditions being a bit on the drier side. Rate could easily overpower the urbanized regions are always slow to drain. Severe weather? Still possible through the afternoon and perhaps early evening hours. CAPE values from this morning`s sounding were also a bit impressive for 7am. Generally around 2200 J/KG. Although heating will take place, there will be cloud cover, which will overall limit destabilization during peak heating. Limited upper ascent will also keep any severe threat on the lower end of the scale. That said, with surface lifting (front) and plenty of instability, continued mentioning strong to isolated severe storms through the remainder of today. Going into Wednesday, the front will slowly begin to move northward. Since we will still be within close proximity, continued rain chances through peak daytime heating. A few thunderstorms can be expected, but the lackluster parameters should continue to limit the overall severe weather threat. We`ll need to continue to watch exactly where showers and storms develop and if the aforementioned scenario with the front stalling over the Atlantic comes to fruition...what impact would that have on the possible hydro situation. Regardless temperatures should generally remain above average for both overnight low and daytime highs through the period. Long term (Wednesday Night through Monday): Models show a rather short-lived ridging/drier period from Wed night through Thursday night as high pressure establishes over the region in the wake of the front`s departure. Subsidence and drier air will bring POPs down to single digits by Thursday afternoon, along with afternoon highs hitting the mid to upper 80s. For Friday, models depict a longwave trough over the Gulf region approaching and dragging a sfc front with it. So far consensus is not too excited about potential for significant impactful weather with this frontal passage, with mainly a narrow line of showers and embedded thunder moving across SoFlo associated with the leading edge of the boundary. Current timing has the front clearing the peninsula Friday afternoon or evening, followed by a short period of lingering post-frontal clouds and patchy light precipitation. Drier and much cooler air will then pour into South Florida Friday night through next weekend. Temperatures will remain well above normals through Thursday, then highs cool down into the low-mid 70s for the weekend behind the FROPA. Quiet weather continues into early next week easterly flow returning and slowly moderating temperatures. MARINE... Showers and thunderstorms are expected over the local waters as a frontal boundary stalls across the area. Locally hazardous boating conditions are possible with lightning, gusty winds, and waterspouts as potential hazards. More favorable marine conditions return by late week as the front lifts away to our north and high pressure rebuilds into the area. BEACH... Elevated rip current potential will continue along the Palm Beach County Beaches through Wednesday. Although winds may shift to offshore, the northeasterly swell will continue to create rip current risks. && .PRELIMINARY POINT TEMPS/POPS... Miami 71 83 74 85 / 30 30 0 0 West Kendall 69 85 72 86 / 30 30 0 0 Opa-Locka 69 83 72 84 / 30 30 0 0 Homestead 69 83 73 84 / 30 20 0 0 Fort Lauderdale 71 83 74 85 / 30 40 0 0 N Ft Lauderdale 71 82 73 83 / 40 40 0 0 Pembroke Pines 70 84 73 85 / 30 40 0 0 West Palm Beach 68 82 71 83 / 40 40 0 0 Boca Raton 70 83 73 85 / 40 40 0 0 Naples 65 83 69 83 / 10 20 0 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && $$ Update...Weinman Tonight/Wednesday and Marine...HVN Wednesday Night through Tuesday/Aviation...AR Visit us at Follow us on Facebook and Twitter at:
Area Forecast Discussion
National Weather Service Paducah KY
749 PM CST Tue Feb 16 2021 .UPDATE... Issued at 749 PM CST Tue Feb 16 2021 Initially clear and nearly calm conditions have allowed temperatures to plummet over much of the region. Many locations have already reached zero or below. The RAP guidance seem to have the best clue to sub-zero temperatures over the snowpack, so sprinkled it in liberally. As clouds increase and winds pick up a bit, temperatures are likely to rebound quite a bit by daybreak Wednesday. UPDATE Issued at 552 PM CST Tue Feb 16 2021 The AVIATION section has been updated for the 00Z TAF issuance. && .SHORT TERM...(Tonight through Thursday night) Issued at 400 PM CST Tue Feb 16 2021 Big challenges in the short term. Confidence levels medium at best. Yet another mid level short wave is expected to shift eastward into the Plains later tonight and Thursday, as surface low pressure lifts ene out of the nrn Gulf and into the southeastern part of the country. A leading northern branch short wave is also expected to lift ne into the MO River Valley overnight. This wave will likely bring an are of light snows to portions of se MO overnight, but the system flattens and runs into dry air as is tries to make its way across the MS River Wednesday AM. Will leave the current winter weather advisory in place to cover generally a 1-2" snow possibility (locally higher near the Ar/MO border) toward the AM commute. The main short wave coming out of the southern Plains is a bit problematic. The global EC/GFS deterministic models show less phasing of another H50 northern branch feature with the stronger southern branch as it moves farther east Wednesday into Thursday, thus shunting most of the more significant moisture off to our south in TN. However, the 18Z NAM, the 12Z GEFS and the 12Z HREF indicate more phasing of the branches as the system moves east, and hence suggest a greater snow potential farther north into our CWA, esp Wednesday night into Thursday. I decided at this point to lean more toward this type solution, especially given the tendency for north/west shift of precip shields with time during past/recent events. Therefore, along with collab from adjacent WFOs, have opted to go ahead and issue a winter storm watch with this forecast package for about the southern half of the forecast area (east of the MS River). Many of these aforementioned higher resolution models suggest the potential for a good 2-4" swath of snow late Wednesday/Wednesday night into at least Thursday morning, with locally higher amounts possibly esp near the KY/TN border region. It is important to note that confidence levels at this time are at the low end of what we normally like to have for winter storm watch issuance. Stay tuned, as adjustments will be probable as the possible event nears in the next 24 hours. .LONG TERM...(Friday through Tuesday) Issued at 400 PM CST Tue Feb 16 2021 After a week of winter storms, Friday will finally bring a start to quieter conditions, but not yet warming. Behind the Wednesday- Thursday system the trough deepens a little more across the area bringing yet another frigid day with highs in the 20s. Partial cloudiness will offset some of the temperature drop overnight, but lows in the mid single digits to lower 10s are likely due to relatively light winds and continued snow cover. On Saturday, the stubborn upper-level trough is finally pushed off to the east, beginning a northwesterly flow aloft and a warming trend. High pressure in the east and a developing low emerging from the Colorado Front Range will help keep winds southerly across the Quad State. While warm advection will be ongoing, snow cover will keep temperatures limited mainly to the low to mid-30s for Saturday. Heading into Saturday the streak of days at or below freezing is expected to be at 10 days for Paducah (tied for 4th longest) and 11 days for Evansville (tied for 11th longest) assuming these continue through Friday. Saturday may add one last day to those counts. If not Saturday then Sunday will bring an end to below average temperatures, with highs near or above 40 degrees. The low pressure system in the Central Plains is expected to move northeastward, crossing to the north of the Quad State overnight. The operational models are in moderately high agreement on a line of mainly rain showers (some mixing of snow is possible Sunday night) developing from the Great Lakes down towards the Gulf Coast. The Canadian brings the line through during the day while the GFS/ECMWF wait until Sunday night. Ensembles seem to be somewhat similar on average to the operational. QPF remains fairly light, between a tenth and a quarter of an inch, primarily as rain. While the line of rain Sunday would likely be accompanied by a frontal passage, the disruption to the warming 2trend and southerly flow is likely to be temporary, with highs potentially near 50 by Tuesday. && .AVIATION... Issued at 552 PM CST Tue Feb 16 2021 MVFR ceilings and some areas of light snow may linger through the evening in the KHOP area, but elsewhere, VFR conditions are forecast for most of the night. Our next round of light snow will overspread southeast Missouri overnight, and may reach KCGI and KPAH by 12Z. A period of MVFR snow is expected at those sites, but MVFR ceilings will arrive a few hours later as visibilities improve. Some VFR light snow may reach the other TAF sites by 18Z, and cannot rule out a very brief period of MVFR snow at KOWB. MVFR ceilings should prevail over the entire area through the afternoon. The next and more significant area of snow may reach KCGI and KPAH near the end of the period. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Winter Storm Watch from Wednesday afternoon through Thursday afternoon for ILZ088>094. MO...Winter Storm Watch from Wednesday afternoon through Thursday afternoon for MOZ112. Winter Weather Advisory from midnight tonight to noon CST Wednesday for MOZ076-086-087-100-107>111-114. IN...None. KY...Winter Storm Watch from Wednesday afternoon through Thursday afternoon for KYZ001>013-015>017-020>022. && $$ UPDATE...DRS SHORT TERM...ATL LONG TERM... AVIATION...DRS
Area Forecast Discussion
National Weather Service Riverton WY
221 PM MST Tue Feb 16 2021 .SHORT TERM...Tonight through Wednesday night Light snow continues to fall across the west as this latest system continues to overperform across the higher peaks. The northwest flow pattern will continue, and with it, chances of snow across the western mountains. In terms of additional snowfall amounts, the higher peaks of the Tetons and Salt/Wyoming Range will see another 6 to 8 inches with locally higher amounts possible. The Absarokas and Gros Ventres will see another 2 to 4 inches, again with locally higher amounts, especially along the eastern edge of Yellowstone Park. The western valleys are not looking at much additional accumulation with generally 1 to 2 inches expected. These amounts are through Wednesday morning. Heavier snow will fall through 11 PM tonight. Wednesday morning, a quick-hitting shortwave will sweep northern Wyoming with a piece of energy that will cause some higher snowfall rates early Wednesday afternoon. This energy will also bring some snowfall to northern Wyoming. This snow will be banded in nature, which means snowfall amounts are generally very difficult to pin down. Kept general PoPs across the Bighorn Basin and Owl Creeks and into northern Johnson County tonight through Wednesday afternoon to account for the uncertainty in the bands. The HRRR and 4km NAM both show banding coming off of the southern Absarokas and Bighorns, which could mean some of the bands may reach as far as Riverton and Lander as well as Casper, but again, uncertainty is very high with banded snowfall like this. Amounts under the bands doesn`t look to be more than an inch or two, as there is not much moisture and these bands will be quick-moving. Temperatures will continue to push closer to normal. Some locations are seeing 30 for the first time in over a week today. Those same locations will come close to 30 again tomorrow, but the quick- hitting system and cloud cover will keep temperatures cooler than the otherwise would be for tomorrow. Lows will continue to be in the low teens to single digits, but should be above zero east of the Divide. The Green River Basin and cold valleys in Yellowstone may see lows a few degrees below zero, especially Wednesday night if skies clear out enough. Winds will remain mostly light through the next day or so with some breezy conditions during the afternoon across the southern Wind Corridor, including Rock Springs. Winds will diminish overnight, as is the norm, and increase again after sunrise. .LONG TERM...Thursday through Tuesday The period should start off fairly quiet with decreasing snow showers as moisture gradually moves away and transitory ridging builds across the Cowboy state. This should bring a period of around 24 hours or so of mainly dry and quiet weather. The next in the series of Pacific waves will move into the west on later Thursday night into Friday with the next chance of snow. At this point, this does not look like a huge storm. However, it could be enough for some advisory level snow, especially in the mountains. It could also bring some snow to Interstate 80 Friday morning, causing some travel problems. The big question in this period is what happens with the Saturday system. And like the previous shifts, the models are not in good agreement with the position of the jet streak that will define where the snow will be. The GFS continues to be further north and brings a good stripe of snow across much of the southern two thirds of Wyoming from Saturday into Saturday evening. Meanwhile, the European is further south and keeps the snow largely across southern Wyoming, although it has trended a bit further north than the previous run. For now, we made few changes to continuity but this has the potential to be a decent snow for many areas if things work out right. Uncertainty increases starting on Sunday. A few waves will move through what looks to be a west to northwest flow. At this point, it looks to more of an upslope / downslope pattern with some snow showers in the west and mainly dry conditions east. Details on timing and intensity are still uncertain though. Source region of the air mass looks to remain largely Pacific, so any outbreaks of Arctic air look unlikely. && .AVIATION...00Z Issuance West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals Steady snow should taper to showers tonight at KJAC, although showers remain possible through the night with occasional mountain obscurations possible through the night. Largely VFR conditions will occur elsewhere although a stray shower can`t be ruled out at KBPI and KPNA. Gusty winds at KRKS should decrease tonight with lighter wind expected tomorrow. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals VFR conditions continue through the next 24 hours for most locations. A few locations will have the chance of snow showers or snow bands into the evening, but confidence is low in pinpointing them. As a result, we have gone with VCSH for most locations. Any snow showers should end late tonight. More snow showers are possible tomorrow but should not be as numerous. Occasional mountain obscurations will be possible in any snow shower or snow band. && .FIRE WEATHER... Snow continues across western areas through Wednesday. Some snow banding is possible across northern areas tonight and Wednesday. Snow bands may reach as far south as the central Wind River Basin. Western mountains will see another 3 to 6 inches with higher amounts in the Tetons ans Salt/Wyoming Ranges. Valleys and areas east of the Divide will see an inch or two of snow through Wednesday. Smoke dispersal will be poor to fair with light winds expected. Most areas will remain mostly cloudy through Wednesday and clearing Wednesday night into Thursday. Temperatures will be more seasonal through the rest of the week. The next significant chances of snow will be Friday through the weekend. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 11 PM MST this evening for WYZ012- 013-023-024. && $$ SHORT TERM...Fisher LONG TERM...Hattings AVIATION...Hattings FIRE WEATHER...Fisher